What’s the News: Researchers have unearthed the largest fossilized spider yet, announced in a study online today in Biology Letters. The fossil, a Jurassic Period ancestor of the modern orb-weaver spider, gives scientists a glimpse not only into the evolutionary history of orb-weaver spiders, but how these ancient arachnids might have impacted the evolution of insect species that could be snared in the webs.

How the Heck:

The fossil, found preserved in volcanic ash in the Daohugou fossil beds in northeastern China, dates back 165 million years. The researchers dubbed the species Nephila jurassica.

The spider’s formidable prey-catching ability likely drove the evolution of the medium-to-large insects it fed on, as those species scrambled to survive, the researchers wrote.

What’s the Context:

Until now, the earliest known fossil from the Nephila genus was 34 million years old; this find pushes back the origin of the genus 130 million years from what researchers previously thought.

Modern orb-weaver spiders live in tropical climes, so this fossil suggests that the region where it was found may have had a much muggier climate during the Jurassic than it does today.

The oldest fossil spiders ever found are nearly twice as old as this specimen, dating back 310 million years.

While its size is remarkable for a fossilized spider, Nephila jurassica‘s legspan is only half as big as that of the world’s largest living spiders, the evocatively named goliath bird-eater and giant huntsman.

This is an exciting find–one in a long line of fascinating discoveries by Paul Selden. Correction: spiders’ spinnerets are always located on their abdomen, never on their legs. If you’d like to learn more about spider evolution, including how the golden orb webs of Nephila spiders drive and have been driven by the evolution of insect eyesight, I think you’ll like the book I co-authored with arachnologist Catherine L. Craig, Spider Silk: Evolution and 400 Million Years of Spinning, Waiting, Snagging, and Mating (Yale University Press, 2010). See http://www.lesliebrunetta.com/bio.htm for reviews.

Srowitt

Well, yet another example of a living fossil. Ain’t Mother Nature wonderful?